Method of making individual bowling



July 5, 1955 w. L. STERCZEK METHOD OF MAKING INDIVIDUAL BOWLING BALL GRIPS Filed Feb. 21, 1951 FIG. I.

FIG. 2.

F IG. 4.

A/dflZL WENTOR United States Patent METHOD OF MAKING INDIVIDUAL BOWLING BALL GRIPS This invention relates to a method of making individual bowling ball grips and has for its primary object accurately to produce in a bowling ball, comfortable cavities conforming to the shape of a thumb and at least one finger of the user to insure accuracy in the holding of the ball preparatory to its delivery.

Another object is accurately to reproduce a cast of the hand of an individual in gripping position with relation to a bowling ball, which cast may be utilized in the formation of the ball to insure accuracy of the grip.

The above and other objects may be attained by employing this invention which embodies among its features first making an impression of the hand of an individual in a gripping and prior to releasing position, forming a cast in the impression, supporting the cast in a mold in which a ball is to be formed, forming the bowling ball about the cast and subsequently removing the cast and finishing the ball.

Other features include forming the cast in the impression introducing the cast into a mold having at least a portion of its surface conforming to the configuration of the bowling ball introducing bowling ball forming material into the mold around the cast and subsequently removing the cast and finishing the item so molded.

Still other features include forming a plug about a cast conforming to the thumb and at least one finger of an individual, removing the cast from the plug, finishing the surrface thereof and introducing the plug into a cavity in a bowling ball to produce a sphere having cavities therein conforming to the shape of the thumb and at least one finger of the individual in gripping position.

In the drawings:

Figure l is a side view partly in section of a mold in which the impression is made of the thumb and at least one finger of the individual to use the ball.

Figure 2 is a view similar to Figure 1 showing the thumb and finger removed and the cast in the process of being made,

Figure 3 is a view illustrating the cast in place in a mold in which a bowling ball is to be formed.

Figure 4 is a side view of the mold illustrating the cast in dotted lines.

Referring to the drawings in detail a form 15 preferably of hemi-spherical shape conforming generally to the size and contour of one half of the bowling ball is provided with spaced cavities 16 and 17 into which a shape retaining substance 18 such as liquid rubber, plaster or plastic is introduced. This substance has the property of setting slowly upon exposure to air and after introducing the substance into the cavities 16 and 17 the thumb and at least one finger of the individual for whom the bowling ball is to be made is introduced into the cavities so as to cause an impressionto be formed in the shape retaining substance 18 so that the contour of the cavities formed in the substance 18 will conform to the size and shape of the finger and thumb with proper provision made for clearance which is needed when ball is thrown. Flexible, snug fitting tubing of previously determined thickness ties previously referred to.

Patented July 5, 1955 ice can be slipped over the finger and thumb when melting the impression for cast 22. Use of said tubing will make possible that the cavities 28 and 29 will have clearance which is necessary for repetitious, comfortable and accurate delivery of ball. 1

It is to be understood of course that while ,in themajority of instances bowling balls are formed with only .two cavities 16 and 17 a third may be employed for the:introduction of another finger and an impression formed thereof as above described. After setting of the plastic substance 18 a font 19 is mounted upon the form 15 as shown in Figure 2 and a low melting point alloy 20 is introduced in liquid form into said font from a suitable container such as a crucible 21.

Upon the setting of the alloy 20 and its conversion from a liquid to a solid state the cast 22 made therefrom is removed from the form 15 and the impressions 18 and is introduced into a mold half 23 in which one portion of the bowling ball is to be formed. The other mold half 24 is then placed in position on the mold half 23 and ball forming material 25 is loaded into the mold so as to surround the projections 27 on the cast 22 as illustrated in Figure 3 and thus form the cavities. Having introduced the material 25 into the mold parts 23 and 24, and around the projections 27 of the cast 22, the ball forming mate'- rial is subjected to heat and pressure, between the mold halves. Said heat and pressure forms a spherical body conforming to the size and shape of a bowling ball and when the material is set and cured, the mold halves 23 and 24 are separated and the ball thus molded together with the cast 22 is removed from the mold.

In as much as the cast 22 is made from a low melting point alloy, it is obvious that the cast 22 may be readily melted from the spherical body so as to leave the cavi- Having completed the ball with the cavities therein the surfaces are finished and polished in the ordinary manner. It will thus be seen that the ball will be provided with cavities conforming to the shape of the thumb and finger or fingers respectively of the individual from whose thumb and finger or fingers the cast 22 was made. As a consequence a natural and comfortable grip will be provided in the ball.

In the mold, the opening 26 is used as a vent and/or chamber where excess ball forming material can accuniulate during the heat and pressure operation, and

through which opening 26 positive or auxiliary pressure can be applied, depending on the specific requirements.

of the chosen ball forming material which may be used. Screw plug 30 is fitted to opening 26, said screw plug 30 being used to close opening 26 when the molding process peculiarities of the ball forming material should demand it.

From the foregoing it will be obvious that new bowling balls may be made having custom fitted grips and where so desired balls already produced may be fitted with custom fitted grips according to the desires of the user. Such custom fitted grips assure accurate handling of the ball and provide comfort for the user by eliminating the fatigue that frequently accompanies the use of a bowling ball having grips of improper span or shape of the finger hole.

It is to be understood that minor changes may be made in carrying out the process and that the invention is not limited to the use of rubber, plaster or plastic but that any suitable shape retaining substances and low melting material may be substituted should occasion demand.

What I claim is:

The hereindescribed method of making an individual bowling ball grip which includes, forming a body having a spherical contour conforming to the curvature of a bowling ball, forming at least two cavities in the body to receive the thumb and at least one finger of the individual for whom the grip is to be made, introducing a flowable, shape retaining substance into the cavities, introducing the thumb and at least one finger of the individual into the fiowable, shape retaining substance to form an impression thereof in said substance, removing the thumb and finger or fingers, pouring a low melting point material in the impressions to produce a cast of the thumb and finger or fingers, introducing the cast thus formed into a mold, filling the mold with ball forming material, forming a ball in the mold about the cast, melting the cast to leave cavities in the ball conforming to the size and shape of the thumb and fingers of which the cast .was made and finishing the ball.

UNITED STATES PATENTS Davis Oct. 8, Richards Feb. 10, Walter Jan. 10, Errington et al. Sept. 23, Hess s July 13, Feinbloom Sept. 6, Raiche- July 7, Lennington Feb. 15,

' Kramer Sept. 20, 

